Selective hydrogenation catalyst designed for raw gas feed streams

Abstract

A catalyst for selective hydrogenation of acetylenes and diolefins, particularly in a raw gas feed stream for front end selective hydrogenation. The catalyst contains a low surface area carrier with a surface area from about 2-20 m2/g, wherein the pore volume of the pores of the carrier is greater than about 0.4 cc/g, at least 90 percent of the pore volume of the pores is contained within pores having a pore diameter greater than about 500 Å and about 1 to about 2 percent of the total pore volume is contained in pores with a pore diameter from about 500 to about 1,000 Å. The palladium comprises about 0.01 to about 0.1 weight % and a Group IB metal comprises about 0.005 to about 0.06 weight % of the catalyst.

1. A method for the manufacture of a catalyst for the selective hydrogenation of acetylene and diolefins comprising:
 a) preparing a carrier having a low surface area of about 2 m 2 /g to about 20 m 2 /g and having a pore volume of greater than about 0.4 cc/g, wherein at least 90% of the pore volume is contained in pores having a pore diameter greater than about 500 Å and about 1% to about 2% of the pore volume is contained in pores having a pore diameter of about 500 Å to about 1,000 Å, 
 b) impregnating the carrier with a palladium metal source, 
 c) reducing the palladium impregnated catalyst, 
 d) washing and drying the reduced palladium catalyst, 
 e) impregnating the catalyst with a Group IB metal additive source, 
 f) reducing the Group IB metal additive source, and 
 g) washing and drying the reduced catalyst to form a catalyst for use in the selective hydrogenation of acetylene and diolefins. 
 
     
     
       2. The method of  claim 1  wherein the palladium metal source comprises about 0.01 weight % to about 0.1 weight % of the catalyst, the Group IB metal additive comprises about 0.005 weight % to about 0.6 weight % of the catalyst, and the ratio of the Group IB metal to the palladium is about 0.5:1 to about 6:1. 
     
     
       3. The method of  claim 1  wherein the Group IB metal additive is silver. 
     
     
       4. The method of  claim 1  wherein the palladium metal source is impregnated into the carrier to a penetration depth up to about 250 microns from the surface of the catalyst. 
     
     
       5. The method of  claim 1  wherein the palladium metal source is impregnated into the carrier such that at least about 90 weight % of the palladium metal source is located within about 250 microns of the surface of the catalyst. 
     
     
       6. The method of  claim 1  wherein the catalyst comprises about 0.01 weight % to about 0.03 weight % palladium and about 0.01 weight % to about 0.12 weight % of a silver additive. 
     
     
       7. The method of  claim 1  wherein the carrier is selected from the group consisting of alumina, silica-alumina, zinc oxide, nickel spinel, titania, zirconia, ceria, chromia-alumina, magnesia and mixtures thereof. 
     
     
       8. The method of  claim 1  wherein the carrier is alumina. 
     
     
       9. The method of  claim 1  further including forming the carrier in a shape selected from the group consisting of a sphere, trihole, monolith, pellet and tablet. 
     
     
       10. The method of  claim 1  further including forming the carrier in a spherical shape having a diameter of about 1 millimeter to about 5 millimeters. 
     
     
       11. The method of  claim 1  wherein the carrier is prepared having a surface area of about 2 m 2 /g to 20 m 2 /g. 
     
     
       12. A method for the manufacture of a catalyst for the selective hydrogenation of acetylene and diolefins comprising:
 a) preparing a carrier having a low surface area of about 3 m 2 /g to about 5 m 2 /g and having a pore volume of greater than about 0.5 cc/g, wherein at least 98% of the pore volume is contained in pores having a pore diameter greater than about 500 Å and about 1% to about 2% of the pore volume is contained in pores having a pore diameter of about 500 Å to about 1,000 Å, 
 b) impregnating the carrier with palladium, 
 c) reducing the palladium impregnated catalyst, 
 d) impregnating the catalyst with silver, and 
 e) reducing the silver to form a catalyst for use in the selective hydrogenation of acetylene and diolefins. 
 
     
     
       13. The method of  claim 12  wherein the palladium comprises about 0.01 weight % to about 0.03 weight % of the catalyst, the silver comprises about 0.01 weight % to about 0.12 weight % of the catalyst, and the ratio of the silver to the palladium is about 1:1 to about 4:1. 
     
     
       14. The method of  claim 12  wherein the palladium is impregnated into the carrier to a penetration depth up to about 250 microns from the surface of the catalyst. 
     
     
       15. The method of  claim 12  wherein the palladium is impregnated into the carrier such that at least about 90 weight % of the palladium is located within about 250 microns of the surface of the catalyst. 
     
     
       16. The method of  claim 12  wherein the carrier is selected from the group consisting of alumina, silica-alumina, zinc oxide, nickel spinel, titania, zirconia, ceria, chromia-alumina, magnesia and mixtures thereof. 
     
     
       17. The method of  claim 12  wherein the carrier is alumina. 
     
     
       18. The method of  claim 12  further including forming the carrier in a shape selected from the group consisting of a sphere, trihole, monolith, pellet and tablet. 
     
     
       19. The method of  claim 12  further including forming the carrier in a spherical shape having a diameter of about 1 millimeter to about 5 millimeters.